Week 4 – Eagle on ‘might’ counterfactuals
May 22, 2009
This week we discussed some unpublished material by Antony on ‘might’ counterfactuals. The handout is here, and the paper is here.
We thought a bit about cases in which ‘could’ and ‘might’ come apart. In the paper, Antony discussed sentences like
33b) If we’d left the gate open, the dog could have got out; yet if we’d left the gate open, it isn’t the case that the dog might have got out.
The felicity of such sentences seems to show that at least some ‘might’ counterfactuals shouldn’t be analysed in terms of ‘could’, but instead should be given an epistemic reading. Antony isn’t averse to this idea – in fact, his final view is that ‘might’ is ambiguous in counterfactual contexts between the epistemic reading and the ability reading. However, this does invite the further question of what determines the appropriate reading for some given ‘might’ counterfactual.
Fron 33b we naturally conclude though the dog has the ability to get out, it is so disposed as to not exercise this ability. The only way to interpret someone who expresses the conjunction as not contradicting themselves is to give the ‘might’ and the ‘could’ different readings, and the ‘could’ tends to snaffle the ability reading, leaving the epistemic reading for the ‘might’. 33a, on the other hand, is intuitively clashing:
33a) If we’d left the gate open, the dog might have got out; yet if we’d left the gate open, the dog couldn’t have got out.
An explanation for this would be is that the ‘might’ in the first conjunct naturally takes an ability reading, which the second conjunct then contradicts. If this is right, then it looks like ‘the dog couldn’t have got out’ always takes an ability reading, while ‘the dog might have got out’ can take both the ability and epistemic readings.
This suggests the following difference between ‘might’ and ‘could’ in counterfactual contexts. When used as a predicate, as in the examples above, can/could always takes the ability reading. It only takes the epistemic reading when used as a sentence modifer, as in ‘it could be that the dog escaped’. May/might, on the other hand, can take either the epistemic reading or the ability reading when used as as a predicate. Like can/could, may/might always takes an epistemic reading when used as a sentence modifier.
On a separate issue, I wondered about how use of ‘might’ outside of counterfactual contexts fits with the duality account of the relationship between ‘might’ and ‘would’. Assume Goldbach’s conjecture is necessarily true. On a Lewisian account, there are no worlds in which Goldbach’s conjecture is false, so any counterfactual of the form ‘If x were the case, Goldbach’s conjecture might be false’ comes out false. As Williamson has argued, it seems a plausible principle of counterfactual logic that ‘if, whatever were the case, then p’ entails that necessarily p. Putting this together, the Lewisian account of ‘might’ in counterfactuals contexts entails that ‘Goldbach’s conjecture might be false’ is necessarily false. This is a bad result; we want to say that lots of speakers speak truly when they assert Goldbach’s conjecture might be false’, if their epistemic state is such as not to rule out its falsity. I’m sure this has been observed before; I’d be glad of any references.
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1.
Lee Walters | May 22, 2009 at 2:04 pm
An altenative explanation for
33a) If we’d left the gate open, the dog might have got out; yet if we’d left the gate open, the dog couldn’t have got out.
is that the ‘might’ in the first conjunct expresses an epistemic reading, and the ‘could’ in the second conjunct takes an ability reading. the clash then being explained by some principle that if it is known that a does not have the ability to F, then it is not epistemically possible that Fa and a knowledge norm of assetion. This explanation is more complex but doesn’t strike me as obviously wrong.
Also I’m not sure what you say about GC is correct. For lewis, the ‘might’ is part of the connective not the consequent. To apply Williamson’s principle of counterfactual logic you would need ‘if x, then it would not be the case that GC might be true’. But Lewis can reject this. Does this make sense?
2.
Alastair | May 23, 2009 at 10:39 am
Thanks Lee – both points well taken.
Your explanation of the clash in the case of 33a seems a good one to me. But I suppose there could be more than one reason why 33a clashes – perhaps both explanations are in play to rule out different joint readings of the two modals. The sentence sounds bad because we can’t find an acceptable joint reading – unlike in 33b where the ability/epistemic reading makes sense.
You’re right, of course, about the Lewis connective view – thanks. I suppose that just shifts my worry to: how does this connective use of ‘might’ in counterfactual contexts tie in with its other uses? Here I suppose we can say that the same ambiguity between epistemic and ability readings exists in the same way in simple ‘might’ sentences – it doesn’t seem implausible to give ‘the dog might get out’ an ability reading even outside counterfactual contexts. An example where it seems to demand the ability reading:: ‘I might have got up earlier today, but decided to be lazy.’
If the same sort of ability/epistemic ambiguity is also present in normal ‘might’ sentences, we’d expect ‘the dog could get out, but it’s not the case that he might get out’ as felicitous, but ‘the dog might get out, but he couldn’t get out’ as infelicitous. And that seems right.
One neat thing about the idea that, used as predicates, ‘could’/'can’ always takes the ability reading but ‘may’/'might’ takes both an ability and an epistemic reading is that it gives us the germ of an explanation for their different behaviour under negation, which Eagle notes just to deny that it is a problem. Since ‘could’ has to take the ability reading, ‘could not’ in a counterfactual context like 34a has to be interpreted as ascribing a lack of an ability. The alternative, ascribing the presence of an ability to not do something, is rarely useful conversationally (though 34a can be read that way at a stretch). 34b on the other hand is naturally read epistemically, and ascribing the epistemic possibility of someone’s not doing something is not at all conversationally unusual.